Such plastic rocker pendulums are used, among other things, in the manufacture of motor vehicles, and manufacturing of the rocker pendulums from plastic has, in general, proved to be successful. The material used offers significant advantages especially in respect to the connection between the mounting elements and the ball heads, because the ball heads can be snapped directly into the mounting elements designed as matching ball sockets because of the elastic properties of the plastic. The process of mounting the components to be connected to one another is significantly simplified hereby and the mounting costs are comparatively low.
The use of the plastic material does, however, have the drawback that the elasticity, which is necessary, on the one hand, for the above-described mounting process, calls, on the other hand, for a substantially lower modulus of elasticity compared to other materials, especially metal, so that the absorption of forces and here especially of buckling loads is considerably reduced compared to metallic materials. The low load limit can be compensated, within certain limits, on the one hand, by increasing the cross-sectional dimensions, and, moreover, there is a possibility of bringing about an increase in the geometrical moment of inertia and hence of the load-bearing capacity of the overall construction by a special design of the cross section.
Special cross-sectional designs for the rocker pendulums of this class described are known, for example, from DE 25 39 698 A1. A construction called torsion bar linkage, which comprises a connection rod made of plastic with ball sockets formed integrally from the same plastic in one piece at its two ends, and wherein ball pins are snapped in a sealed manner into the ball sockets, is described in this document. The torsion bar linkage consists as a whole of polyurethane, and the connection rod has an H-shaped cross section with a relatively thin web and thin flanges.
Moreover, it can be determined from U.S. Pat. No. 5,352,059 that the basic body of this class may have a plurality of webs arranged next to each other, which are connected to one another by means of a connection web arranged approximately centrally. Such an arrangement has a geometrical moment of inertia that is increased by approx. 30% compared to that of the embodiment known from the aforementioned document, an equal space (outer circle of the cross sections as a reference variable) being used for the calculation in each case.
The cross sections known so far are definitely sufficient for numerous applications and the loads arising there, but the solutions known from the state of the art reach their limits in case of special requirements with increased load values and restricted space dimensions.